Bottom hole housing for fluid operated pump



BOTTOM HOLE HOUSING FOR FLUID OPERATED PUMP Filed Feb. 25, 1957 Nov. 3, 1959 c. J. coBERLY 2 Sheets-Sheet 1 rl .4.1.3.1 JA LT IJLL @l ai ffl@ Nov. 3, 1959 C, J, COBE'RLY 2,910,945

BOTTOM HOLE HOUSING FOR FLUID OPERATED PUMP Unite States atent O l BOTTOM HOLE HOUSING FOR FLUID OPERATED PUMP Clarence J. Coherly, San Marino, Calif., assignor to Kobe, Inc., Huntington Park, Calif., a corporation of California Appiication February 25, 1957 Serial No. 642,127

9 Claims. 4(Cl. 10S-46) The present invention relates generally to fluid operated oil well pumping systems and, more particularly, to a housing for a bottom hole, fluid operated oil well pump, this application being a continuation-in-part of my copending application Serial No. 487,303, filed February 10, 1955, now Patent No. 2,869,470, issued January 20, i959. For convenience, the invention will be considered herein in connection with a uid operated free pump system, although it will be understood that various features of the invention may possibly be embodied in a set pump system.

Fluid operated free pump systems normally include either two tubings, or three tubings, one of the tubings in either system being of a size to permit circulating a fluid operated free pump therethrough between the surface and an operating position within a bottom hole housing in the well. In a two-tubing pump system, often called an open system, the production fluid and the spent operating fluid discharged by the pump are mixed and conveyed to the surface in a single production tubing. ln a three-tubing free pump system, commonly called a closed system, the production iuid and the spent operating fluid are conveyed to the surface separately in sep-` arate production and return tubings. As a matter of convenience, the invention will be considered herein in connection with an open system with the understanding that it is not limited thereto.

rThe present invention contemplates a bottom hole housing for the pump which includes at least `two vertically spaced housing members connected by a pump housing tube adapted to receive the pump therein. The present disclosure will be restricted to this basic structure for convenience with the understanding that variations thereof are possible within the scope of the invention. For example, three or more vertically spaced housing members interconnected by two or more pump housing tubes may be utilized.

In the basic pump housing structure elected for con sideration herein, the upper housing member is normally referred to as a sealing collar and the lower housing member as a bottom shoe, the sealing collar and the bottom shoe being interconnected in vertically spaced relation by the pump housing tube. The supply and production tubings are connected to the upper end of the sealing collar and support the pump housing, the return tubing, in the case of a closed system, also being connected to the upper end of the sealing collar. To provide the required fluid interconnections between the sealing collar and the bottom shoe, these members are also interconnected by one or more pipes spaced from and parallel to the pump housing tube, as will be explained in more detail hereinafter.

An important object of the invention is to provide a pump housing of the foregoing nature wherein the pump housing tube interconnecting the sealing collar and the bottom shoe is connected to at least one of these members by means of extended, ie., untapered, threads so 2 ,9 i 0,945 Patented Nov. 3, 1959 being threaded into these members.

Another object is to provide lock nuts threaded on the pump housing tube and respectively engaging the sealing collar and the bottom shoe to lock the pump housing tube, the sealing collar and the bottom shoe together rigidly once the desired vertical relationship between the bottom shoe and the sealing collar has been attained.

Another important object of the invention is to locate at least one end of each of the parallel pipes in a bore in either the sealing collar or the bottom shoe in sliding relation with the wall of such bore to permit vertical adjustment of the relative positions of the sealing collar and the bottom shoe without correspondingly varying the length of the pipe. Preferably, only one end of each parallel pipe is slidable relative to either the sealing collar or the bottom shoe, the other end of such pipe being rigidly connected to the other of these members, as by means of ordinary pipe threads.

The parallel pipes mentioned are subjected to relatively high uid pressures at various times during the operation of the pump system and, if vertical components of these pressures were applied to the sealing collar and the bottom shoe, relatively large bending moments tending to bend the pump housing tube would be applied to this tube due to the eccentric loading resulting from the lateral offset of the parallel pipes from the housing tube.

Another important object of the invention is to eliminate such eccentric loading by applying the iluid pressures in the parallel pipes to these pipes themselves in the vertical direction, instead of to the bottom shoe and the sealing collar, thereby eliminating the application of bending moments to the pump housing tube.

The foregoing elimination of eccentric loading of the pump housing tube is important since it insures free movement of the pump into and out of the pump housing tube. If the eccentric loading of the pump housing tube is not eliminated in this manner, the pump housing tube may bend suiiciently to prevent movement of the pump into and out of the pump housing tube, or to cause scoring of the exterior of the pump. The present invention eliminates these difiiculties, which is an important feature.

The foregoing objects, advantages and features of the present invention, together with various other objects, ad-

, vantages and features thereof which will become apparent, may be attained with the exemplary embodiment of the invention illustrated in the accompanying drawings and described in detail hereinafter. Referring to the drawings:

Fig. 1 is a vertical sectional view on a reduced scale illustrating a Huid operated free pump system which embodies the invention;

Fig. 2 is a sectional view taken along the arrowed line 2 2 of Fig. 1;

Fig. 3 is a vertical sectional View taken along the arrowed line 3 3 of Fig. 2;

Figs. 4'and 5 are downward continuations of Figs. 3 and 4, respectively;

Fig. 6 is a vertical sectional View taken along the arrowed line 6-6 of Fig. 2;

Figs. 7 and 8 are enlarged, fragmentary sectional views duplicating a portion of Fig. 3, but illustrating a latch means in different operating positions;

Fig. 9 is an enlarged, fragmentary sectional View illus` 3 trating means formechanically resetting the latch means; l is a view of one end of the latch means; and 1l is a view of the other end of the latch means. Referring particularly to Fig. l of the drawings, the numeral 12 designates a well casing which is setin a well and which is provided with perforations, not shown, to admit into the casingfiuids from surrounding, productiveV formations. The casing 12 is equipped with a casing head 14 whichl supports parallel production and supply tubings 16 and 1S in the casing, .these tubings extending downwardly below the well fluid level in the casing. rEhe production and supply tubings 16-and 18 communicate at their upper ends with. a four-way valve 20 operated by a handle22, .this valve selectively'connecting the production tubing and the supply tubing with an operating iluid supply line 24 and aproduction fluid disposal line 26.

Thus, by means of the valve 2b, either the production tubing 16, or thesupply tubing 13, may be pressurized with operating fluid `from thesupply line 24.

The production tubing 16 is of relatively large diameter to accommodate a iluid operated free pump unit 28 which may be inserted, into the upper end of the production tubing by removing a closure 36 which may contain the usual 'free pump catcher. The pumpl unit 28 is circulated downwardly through the production tubing 16 by connecting the upper end of the production tubing to they supply line 24 until the pump unit arrives at its operating position in a housing which is designated generally by the numeral 32 and which is an assembly ofl components to be described 'in more detail hereinafter. The housing 32 is connected to the lower end of the production tubing 16 and is also connected to the supply tubing 1S, all as will be discussed in more detail hereinafter.

The pump unit 23 Vincludes a pump 34 to the upper end of which is connected a packer nose 36. Thepump 34,

except for minor external modifications, may be of any4 suitable type andcontains the usual pump and engine, or motor, sections together withivalve means ,for controlling the operation of the engine, or motor, section.l

lThe latter includes a -motor piston which reciprocates a pump piston in the pump section to pump well lluid from the well and discharge it as production fluid in a well known manner. Since such components of the pump 34 are well known in the art, they are not illustrated in the drawings and `arenot described further. herein.

Referring now to Fig. of the drawings, theihousing 32 includes at kits lower end a bottom shoe 14S providing a seat 38 for a standing valve assembly 4t) which extends downwardly into anintake pipe 42 depending from the bottom shoe. Well fluid enters the pump 34 through the standing valve assembly 4ll,fwhich` will be described' The lower end ofthe pumpA in more detail hereinafter. 34 is provided with a tubular well-fluid intake 44 which is insertable into a bore `46m the standing valve assemblyv 40, the intake 44 carrying an O-ring 48 which engages the of a passage `56, Fig. 4, in asealing collar 146forming part of the housing 32. The upper end of the passage 56 communicates with the lower end of the supply tubing 18. Thus, operating lluid may be delivered through the supply tubing 1S, the passage $6, the pipe 54, the ports 5S, the channel 52 and the port Sil to the lower end of the pump $4 to unseat the pump unit 28, i.e., withdraw the well-fluid intake 44 from the bore 46, and move the pump unit upwardly from the housing 32 into the production tubing 416, as will be described in more 4 detail hereinafter. As will be apparent, the O-ring 4S maintains separation between the well fluid in the standing valve assembly 4l? and the operating fluid in the housing 32 at the lower end of the pump 34.

Referring to Fig. 4 of the drawings, the passage 56 communicates intermediate its ends with a port 58 in the sealing collar 146, the latter communicating with the interior of the sealing collar. The pump 34 is provided with operating lluid inlet ports 60 which communicate with the port 58 when the pump unit 28 is in its operating position. Thus,v in order to operate the pump 34, operating liuid under pressure delivered to the supply tubing 18 flows downwardly through the supply tubing, the passage 56 and the port 58 to the operating-Huid inlet ports 60. The latter are isolated by G-rings 62 and 64 engaging a sleeve in the sealing collar 146 to prevent intermingling of the operating fluid under pressure with the production fluid and the spent operating fluid, as discussed in more detail hereinafter.

Referring now to Fig. 6 of the drawings, the pump 34 is provided with outlet ports `66 for spent operating lluid and Vdischarge ports, not shown, for the production fluid discharged by the pump. Both the outlet ports v66 and the discharge ports communicate with the interior of a pump housing'` tube 150 intermediate the O-ring 64 and an O- ring 67 engaging a sleeve 68 in the bottom shoe 148, the tube-150 forming part of the housing 32 and connecting the sealing collar 146 and the bottom shoe 14S, as hereinafter explained. Thus, the O-ring 67 separates the mixture of spent operating fluid and production 'fluid from the'operating uid at the lower end of the pump, and the O-ring 64 separates the mixture of spent operating fluid and production lluid from the operating lluid in the vicinity of the operating-fluid inlet ports 60.

The mixture of spent operating fluid and production iluid flows through `the tube 150 between this tube and the pump 34 to a port '70 in the bottom shoe 148, as shown in Fig; 6 of the drawings. The port 7b communicates with an annular channel 72 in the bottom shoe 148, which channel communicates with the interior of a pipe 74 through ports 75 therein. The pipe 74 leads upwardly to the lower end of a passage 76 in the sealing collar 146, the upper end of the latter communicating through a port 78 with the interior of the sealing collar above the O-ring 62. Thus, the O-ring 62 separates the operating fluid under pressure supplied to the operating-fluid inlet ports 6@ from the mixture of spent operating fluid and production lluid entering the sealing collar 146 above the O-ring 62 by the avenue outlined. The interior of the sealing collar 146 above the O-ring 62 communicates with the lower end of the production tubing 16 through a packer housing tube 90, which forms part of the housing 32, to provide for upward llow of the mixture of spent operating lluid and production fluid therethrough to the surface.

When the pump unit 28 is in the housing 32 with the well-fluid intake 44 in the bore 46, the area of the wellfluid intake 44 is exposed to well fluid pressure and, with operating iluid pressure applied to the supply tubing 18, such operating fluid pressure plus the head of operating fluid are applied to an area of the pump 34 equal to the difference between the area of the pump at the sealing collar 146 and the areaof the well-fluid intake 44. Both the well fluid pressure and the operating fluid press ,re applied to such areas of the pump act upwardly on the pump` unit 23. Acting downwardly on the pump unit over the area of the pump at the sealing collar 146, is the dischargerpressure in the production tubing 16, which is equal to the head of the mixture of spent operating fluid and production fluid in the production tubing. When the pump34 isin operation, the netresult of theforegoing pressure applications to the pump unit is the application of an upward bias to the pump unit tending to move the pump upwardly into the production tubing 16, which, as described in more detail hereinafter, is utilized to circulate the pump to the surface. However, when the pump 34 is in operation, the pump unit 28 is held in its operating positionv in the housing 32 in opposition to such upward bias by a latch means 80 of the invention which will now be described.

Considering the latch means 80 generally, it includes a latch housing 82 which provides a latch guide 84 for latches `86 engageable with a downwardly facing annular shoulder 88 in the tube 90. `Connected to the upper end of the latch housing 82 is a nose 92 which is engageable with a pump catcher carried by the closure 30 as is well known in the art. Connected to the lower end of the latch housing 82 is a packer tube '94 which is connected to the upper end of the pump 34, the interior of the packer tube communicating with the operating-fluid inlet ports 60 so that, when these ports lare in communication with the port 58 and operating fluid under pressure is applied to the supply tubing 18, operating uid under pressure is also present in the packer tube 94 for a purpose to be discussed. The packer tube 94 carries downwardly facing packers 96 and 98 which are disposed in enlarged portions 100 and 182, respectively, of the tube 90 when the pump unit 28 is in its operating position, whereby the mixture of spent operating fluid and production fluid may 'How upwardly past the packers '96 and 98 into the production tubing 16. It will be noted that a clearance is provided between the latch housing `82 and the tube 98 for such upward flow of the mixture of spent operating fluid and production iiuid. Above the lower packer 96 is a reduced portion 104 of the tube 90 with which the lower packer `96 is engageable after the pump has been unseated in a manner to -be described, the lower packer thus forming a seal with the reduced portion 1014 so that operating fluid pressure applied beneath the pump will move the pump unit 28 upwardly in the housing 32. By the time the lower packer '96 reaches the upper end of the reduced portion 104 of the tube 90, the upper packer 98 will be within and making a seal with the production tubing 16 to continue the upward movement of the pump. Ultimately, of course, both the packers 96 and 98 will engage and make seals with the production tubing 16 to enable the operating iluid under pressure delivered below the pump 34 for the purpose of circulating the pump unit 28 out of the hole, to perform its intended function.

Considering the latch means 80 now in more detail, the latch guide 84 has the form of a transverse cylindrical bore through the latch housing 82, and the latches 86 have the form of pistons which are slidable in such bore and which are sealed relative to the wall thereof by O-rings 186. The outer ends of the latches 86 are reduced in diameter slightly and are provided with flats 187, as best shown in Fig. ll. The purpose of this diameter reduction is to permit latch retraction even with a build-up of foreign matter on the outer ends of the latches in use. The two latches 86 are identical but reversed in position, one at 107 on each being engageable with the shoulder 88.

As will be apparent, the outer ends of the latches 86 are exposed to the iluid pressure prevailing in the tube 90 surrounding the pump unit 28, i.e., the outer ends of the latches are exposed to the iluid pressure in the production tubing 16. The inner ends of the latches 86 are adapted to be exposed to operating fluid pressure in the packer tube 94 through passages 108 connecting the interior of the packer tube to the interior of the latch guide 84. As will be discussed hereinafter, when the latches 86 are fully retracted, Fig. 8, the O-rings 106 move across the ends of the passages 108 in communication with the latch guide 84 to prevent application of operating iluid pressure to the inner ends of the latches. The latch guide 84 also communicates with the packer tube 94 through a passage 115i, a chamber 112 and a passage 114. The passage 11@ is adapted to be closed by a check valve 116 to prevent flo-w from the packer tube to the latch guide 84 by way of the passage 114, the chamber 112 and the passage 110. However, the check valve l116 is adapted to unseat to permit ow in the opposite direction, i.e., to permit flow from the latch guide 84 to the packer tube 94 by way of the passage 110, the chamber 112 and the passage 114. The reasons for this will be discussed hereinafter. The latches 86 are provided with inwardly extending spring ngers 118 having laterally projections 128 provided with inner edges 122 and outer edges 124 engageable with a pin 126 extending across the latch guide. When the latches 86 are in extended positions, as shown in Fig. 7 of the drawings, the inner edges 122 of the spring ngers 118 are out of engagement with the pin 126. However, the free ends of the spring lingers 118 still engage the pin 126 under such conditions to prevent rotation of the latches 86 in the guide 84. When the latches are in an intermediate position, as shown in Fig. 3 ot `the drawings, the inner edges 122 of the lateral projections engage the pin 126 to prevent further inward movement of the latches except upon the application of a substantial pressure to the outer ends of the latches. When the latches are in their retracted positions, as shown in Fig. 8 of the drawings, the lateral projections 128 on the spring ngers 118 have moved across the pin 126 so that the outer edges 124 of such projections engage the pin to retain the latches in their retracted positions. It will be noted that, under such conditions, the O-rings 106 on the latches 86 have crossed the ends of the passages 188 in communication with the latch guide 84 to prevent application of operating iluid pressure to the inner ends of the latches 86. Thus, once the latches 86 have been moved into their retracted positions, they cannot be hydraulically extended, for reasons which will be discussed hereinafter.

In order to prevent cooking of the latches 86 by lateral forces resulting from interengagement of the spring iingers 118 and the pin 126, the latches are provided with inwardly extending backup lingers 128. These iingers are provided with slots 130 therein which permit communication between the packer tube 94 and the latch guide 84 through the passages 108 until such time as such communication is cut oft by the O-rings 186.

Considering the over-all operation of the system, prior to running the pump unit 28 into the well, the latches 86 are placed in their intermediate positions so that the inner edges 122 of the lateral projections 128 of the fingers 118 are seated against the pin 126. If the latches 86 are initially in their retracted positions, they may be extended to their intermediate positions by threading a screw 132 thereinto, as shown in Fig. 9 of the drawings. When in their intermediate positions, the latches 86 are iiush with the pump body 34, as shown in Fig. 3 of the drawings. The spring lingers 118 are so designed that they will prevent inward movement of the latches 86 into their retracted positions except upon application of a substantial iluid pressure, e.g., 500 p.s.i.,` to the outer ends of the latches. The pressure required to move the latches 86 into their retracted positions must be higher than the pressure required to circulate the pump into its operating position, 500 psi. being illustrative only.

With the latches 86 in their intermediate positions as hereinberore described, the closure 30 for the upper end of the production tubing 16 is removed, the pump unit 28 is inserted into the upper end of the production tubing, and the closure is replaced. Thereupon the valve 2) is operated to connect the upper end of the production tubing 16 to the operating iluid supply line 24, the valve simultaneously connecting the supply tubing 18 to the production fluid disposal line 26. Preferably, the valve 20 is provided with some means, not shown, for limiting the operating iiuid pressure applied to the production tubing 16 under such conditions to a value less than the pressure required to move the latches 86 into their retracted positions, so as to prevent retraction ofthe latches while the pump is being circulated into its operating position.

Under the foregoing conditions, the pump unit 28 is moved downwardly through the production tubing 16 into the housing- 32, whereupon the well-Huid intake 44 at the lower end of the pump 34 enters the bore 46 in the standing valve assembly 40, downward movement of the pump unit beingterminated by engagement of a shoulder 134 at the lower end of the pump 34 with the upper end of the standing valve assembly. it will be understood, that, as the pump unit 28 moves downwardly through the production tubing 16 into the housing 32, the fluid therebeneath is displaced upwardly to the surface through the supply tubing 18,,being directed from the supply tubing into the disposal line 26 by the valve 20.

The foregoing accomplished, the valve 20 is thenoperated to place the supply tubing 13 in communication with the operating-duid supply line 24 and to place the production tubing 16-in communication with the production-fluid disposal line 26. A relatively low pressure, e.g., 25 to 100 p.s.i., is slowly developed at the upper end of the supply tubing 18, the valve 20 being operated slowly to prevent the development of a pressure under the pump 34 sulicient to unseat the pump unit 28 before the pressure in the latch means 80 builds up enough to extend the latches 86. The relatively low pressure slowly developed in the supply tubing in the foregoing manner is applied, through the packer tube 94 and the passages 108 connecting the packer tube to the interior of the latch guide 84, to the inner ends of the latches 86V to displace these latches outwardly into their extended positions. Such a relatively low pressure, however, is insufficient to move the pump unit 28 upwardly in the housing 32 against frictional resistance `as long as the pressure is allowed to build up slowly so as to minimize the pressure drop in the various passages leading .to the inner ends of the latches.

Subsequently, normal operating uid pressure is developed in the supply tubing 18 to operate the pump 34. When this occurs, the pump unit 28 moves upwardly in the housing 32 until the extended latches 86 seat against the shoulder 88 to limit upward movement of the pump unit, which is now latched in its operating position, shown in broken lines in Figs'. 3 and 5 of the drawings. The pump 34 now begins to operate to pump well fluid from the well by way of the well-fluid intake 44 into the production tubing 16 by the avenue hereinbefore discussed. The operating fluid for operating the pump 34 of course enters the pump through the operating-huid inlet port 60 in the manner hereinbefore described, and the spent operating fluid is mixed with the production fluid and discharged into the production tubing 16, also as hereinbefore discussed. The desired separation between uids is maintained by the various seals described previously.

When it is desired to remove the pump unit 2S, the valve 20 is operated to again place the production tubing 16 in communication with the operating fluid supply line 24. The pressureV in the production tubing 16 is then increased to a value in excess of that required to move the latches 86 inwardly through their intermediate positions into their retracted positions against the resistance offered by engagement of the spring fingers 118 with the pin 126. The pressure necessary to move the latches into their retracted positions is determined by the stiffness of the spring fingers 118 and, as hereinbefore indicated, should exceed the pressure required to circulate the pump unit 28 into the hole. Also, this pressure should be more than any pressure difference resulting from the presence of water in the production tubing 16 which is only partially balanced .by operating fiuid in the supply tubing 18. Upon application of the required pressure to the outer ends of the latches86 by way of the production tubing 16, the latches 86 move inwardly to their retracted positions and are locked therein by engagementof the outer edges 124 of. the lateral projections 120` on the spring ngers 118 with the pin 126. it should be noted that the check valve 116 opens to permit fluid in the latch guide 84 to be displaced 4into the packer tube 94, thereby permitting the latches to move inwardly into their retracted positions. Also, it should be noted that once the latches have been moved into their retracted positions in the foregoing manner, the O-rings 106 have crossed over the ends of the passages 108 in communication with the latch guide 84 to prevent any possibility'of further application of pressure to the inner ends of the latches 86 tending to move them outwardly to their extended positions again as the pump unit 28 is circulated to the surface. The iatches 86 may be reset later, after the pump unit has been removed from the production tubing 16, in any suitable manner, such as the manner illustrated in Fig. 9 of the drawings andk described previously.

Once the latches 86 have been retracted, the valve 20 is. again operated to connect the supply tubing 18 in communication with the operating-huid supply line 24 and to connect the production tubing 16 in communication with the production-duid disposal line 26. Operating iiuid under pressure is .now delivered downwardiy through the supply tubing 18 to move the pump unit 28 upwardly out of the housingl 32 and through the production tubing 16- to the surface. as the pump unit moves upwardly slightly, the lower packer 96 engages the reduced porti-on 104 of the tube 90 to take the operating fluid pressure applied below the pump, the upper'packer 98 shortly thereafter entering the lower end of the production tubing 16 to take the operating fiuid pressure applied below the pump when the lower packer 96 enters the enlarged portion 102 of the tube 90. Eventually, both packers are in the production tubing16-to carry the pump unit upwardly through the production tubing as operating fluid under pressure is delivered to the production tubing below the pump unit through the supply tubing. Once the pump unit 28 reaches the. surface, itis caught by the pump catcher carried by the closure 30, whereupon the closure may be removed to remove the pump unit.

Considering the standing valve assembly 40 in more detail, it includes an upwardly opening check valve 136 of the poppet type adapted to engage a seat 138 and having a hollow stem` 140 disposed in a damping cylinder 142. The check valve 136 is made light in weight and the lit between the stem `140 and the cylinder 142 is such as to give the desired rate of seating. Preferably, the rate of seating is suciently low so that the time required for the check valve to move from its fully open position to its closed position is in excess of ten seconds so that the check valve never seats while the pump 34 is inv operation-,even though the operating speed of such pump is very low. The clearance required to obtain this seating time with a standing valve of the proportions shown is approximately 0.010 inch, i.e., the difference in the diameters of the stem 140 and the cylinder 142 is approximately 0.010 inch. It should be noted that above the valve seat 138 the valve 136 moves through a bore 144 which is only slightly larger than the valve so that there is only a relatively small clearance around the valve until the valve has moved away from the seat 138 a substantial distance, e.g., one-half inch. The valve 136 must, therefore, travel at least this distance from its operating position to its fully closed position, which, with the fit specified between the stem 140 and the cylinder 142, provides a sufficient seating time.

Considering the housing 32, it includes the sealing collar 146 and the bottom shoe 148, into which the upper and lower ends of the pump housing tube 150 are threaded with extended, i.e., untapered, threads and locked by means of lock nuts 152 and 154. Fluid-tight seals are provided betweenl the ends of the tube 150 and the members 146 and 148 by G-rings 156 and 158, respectively.

The hereinbefore discussed pipes 54 and 74, which areparallel-and?spaced-'laterally'lfrom-the tube 150, are threaded into the sealing collar 146 with ordinary pipe Ashereinbefore discussed, as soon,

threads, Figs. 4 and 6, and extend into bores 160 and 162, respectively, in the bottom shoe 148, the channels 52 and 72 'being formed in the walls of the bores 160 and 162, respectively. The lower ends of the pipes 54 and 74 are sealed relative to the walls of the bores 160 and 162, respectively, above the channels 52 and 72, respectively, by O-rings 164 and 166, respectively and are sealed relative to the walls of the bores 160 and 162, respectively, below the channels 52 and 72, respectively, by O-rings 168 and 170, respectively. The effective depths of the bores 160 and 162 must exceed the totals of the distances which the respective pipes extend thereinto and into the sealing collar 146 when completely assembled, this being inherent in the construction illustrated since the bores 160 and 162 extend through the bottom shoe 148.

With the foregoing construction, the lower ends of the pipes 54 and 74 are inserted into the bores 160 and 162, respectively, and the members 146 and 148 and the tube 150 are then assembled and locked with the lock nuts 152 and 154. Under such conditions, the upper ends of the pipes 54 and 74 clear the sealing collar 146, the upper ends of these pipes then being screwed into the sealing collar as shown. Upon assembly, the lower ends of the pipes 54 and 74 are automatically sealed by the O-rings 164, 166, 16S and 170. Thus, the present invention provides a very simple method of assembling the foregoing components of the housing 32. Also, by the use of the extended threads mentioned on the tube 159, the proper relative vertical positions of the sealing collar 146 and the bottom shoe 148 may be established accurately despite dimensional errors arising during manufacture, which is an important feature.

Another important feature of the invention is that the pipes 54 and 74 are closed at their lower ends, as by means of plugs 172 and 174, for example. With this construction, iiuid pressures acting vertically in the pipes 54 and 74, i.e., the vertical components of fluid pressures obtaining in these pipes, do not tend to increase the vertical spacing between the sealing collar 146 and the bottom shoe 148 on one side of the pump housing tube 150 to tend to bend this tube. In other words, if the plugs 172 and 174 were omitted and if the bores 160 and 162 have closed lower ends, as disclosed in my aforementioned co-pending application, vertical pressure components in the pipes 54 and 74 would tend to increase the vertical spacing of the sealing collar 146 and the bottom shoe 143 on the right side of the pump housing tube 150, as viewed in Figs. 5 and 6 of the drawings. This eccentric loading would tend to bend the pump housing tube 150 and, upon application of full operating iiuid pressure, might actually bend the pump housing tube sufficiently to prevent movement of the pump 34 into or out of the housing 32, or to score the exterior of the pump. These difficulties are eliminated in accordance with the present invention by closing the lower ends of the pipes 54 and 74 in the manner described to eliminate the eccentric loading, which is an important feature.

Although I have disclosed an exemplary embodiment of my invention herein for purposes of illustration, it will =be understood that various changes, modifications and substitutions may be incorporated in such embodiment without departing from the spirit of the invention as defined by the following claims:

I claim:

1. A bottom hole housing for a iiuid operated well pump, including: spaced upper and lower members; a tube extending between said members and threadedly connected thereto with extended threads; lock nuts threaded on said tube and engaging said members, respectively, for locking said tube and said members in assembled relation; a pipe Connected to one of said members and extending into the other, the latter member being provided with a bore therein into which said pipe extends and being provided with a passage means which communicates with said bore, the depth of said bore being greater than the difference between the length of said pipe and the distance between said members, said pipe having a port within said bore and communicating with said passage means; and sealing means between said pipe and the wall of said bore, said sealing means being located between said port and that end of said bore into which said pipe extends.

2. A housing as defined in claim l including two sealing means between said tube and said members, respectively.

3. A bottom hole housing for a fluid operated well pump, including: spaced upper and lower members;` a tube extending between and connected toi said members, said tube being threadedly connected to at least one of said members with extended threads; a lock nut threaded on said tube and engaging that member to which said tube is threadedly connected with extended threads to lock such member and said tube inassembled relation; a pipe lconnected to one of said members and extending into the other, the latter member being provided with a bore therein into which said pipe extends and being provided with a passage means which communicates with said bore, said pipe being provided with a port within said bore and communicating with said passage means; and sealing means between said pipe and the wall of said bore, said sealing means being located between said port and that end of said bore into which said pipe extends.

4. A bottom hole housing for a iiuid operated well pump, including: spaced upper and lower members; a tube extending between and connected to said members, said tube being threadedly connected -to at least one of said members with extended threads; a lock nut threaded on said tube and engaging that member to which said tube is threadedly connected with extended threads to lock such member and said tube in assembled relation; a pipe spaced from and parallel to said tub-e and located externally of said tube, said pipe being connected to one of said members and extending into the other, the latter member being provided with a bore into which said pipe extends and being provided with a passage means which communicates with said bore, said pipe being provided with a port within said bore and communicating with said passage means; and sealing means between said pipe and the wall of said bore, said sealing means being located between said port and that end of said bore into which said pipe extends.

5. A bottom hole housing for a fluid operated well pump, including: spaced upper and lower members; a tube extending between and connected to said members, said tube being threadedly connected to at least one of said members with extended threads; a lock. nut threaded on said tube and engaging that member to which said tube is threadedly connected with extended threads to lock such member and said tube in assembled relation; a pipe spaced from and parallel to said tube and located externally of said tube, said pipe being connected to one of said members and extending into the other, the latter member being provided with a bore into which said pipe extends and being provided with a passage means which communicates with said bore, said pipe being provided with a port within said bore and communicating with said passage means, said port being located in the side of said pipe; and two sealing means between said pipe and the Wall of said bore and respectively located above and below said port.

6. A bottom hole housing for a fluid operated well pump, including: spaced upper and lower members; a tube extending between and connected to said members, said tube being threadedly connected to at least one of said members with extended threads; a lock nut threaded on said tube and engaging that member to which said tube is threadedly connected with extended threads to lock such member and said tube in assembled relation; a pipe spaced from and parallel to said tube and located 111 externally of said tube, said pipe being connected to one ofisaid members and extending into the other, the latter member being provided with a bore into which said pipe extends and being provided with a passage means which communicates with said bore, saidpipe being provided with a port within said bore and communicating with said passage means, said port being located'in the side of said pipe; two sealing means between said pipe and the Wall of said bore and respectively located above and below said port; and means closing said pipe at a point on the opposite side of said port from that end of said bore into which said pipe extends, said closing means being) carriedV by said pipe.

7.' A bottom hole housing for a uid operated well pump, including: spaced upper and lower members; a tube extending between and connected to said members, said tube being threadedly connected to at least one of said members with extended threads; a locked nut threaded on said tube and engaging that member to which said tube is threadedly connected with extended threads to lock such member and said tube in assembled relation; a pipe spaced from and parallel to said tube and located externally of said tube, said pipe being threaded into one of said members and extending into the other, the latter member being provided with a bore into which said pipe extends and being provided with a passage means which communicates with said bore, said pipe being provided with a port within said bore and communicating with said passage means, said port'being located in the side of said pipe; two sealing means between said pipe andthe wail of said bore and respectively located above and below said port; and means closing said pipe at a point on the opposite side of said port from that end of said bore into which said pipe extends, said closing means being carried by said pipe.

8. A bottom hole housing for a uid operated well pump, including: spaced upper and lower members; a tube extending between and connected to said members; a

pipe spaced from and parallel to saidy tube and located.' externally of'said tube, said pipe beingy connected to one of said members and extending into the other, thelatter" member being provided with a bore into which said Vpipe extends andibeing provided with a passage means which communicates with said bore, said pipe being provided with a portwitbin said bore and-communicating withV said passage means, said port being located in the side' of saidV i e two sealin" means between said ine and the'wall'ofsaid bore and respectively located above and below' said port; and'means closing said pipe at a point on' the opposite side of said port from that end ofsaid' bore into which said pipe extends, said closing meansV said pipe extends and being' provided with a passageV means which communicates with said bore, said pipe being provided with a port within said bore and communieating with said passage means, said port being located in the side of said pipe; two sealing means between said pipe and the wall of said bore and respectively located above and below said port; and means closing said pipe ata poin-t on the opposite side of said port from that end of said bore into which said pipe extends, said closing means being carried by said pipe.

References Cited in the le of this patent UNITED STATES PATENTS 434,689 Wade Aug. 19, 1890 1,807,117 Kaufman May 26, 1931 2,525,772.v Conery p Oct. 17, 1950 

